External magnetic field suppression of carbon diffusion in iron

Abstract

External magnetic fields reduce diffusion of carbon in BCC iron, but the physical mechanism is not understood. Using DFT calculations with magnetic moments sampled from a Heisenberg model, we calculate diffusivities of carbon in iron at high temperatures and with field. Our model reproduces the measured suppression of diffusivity from field. We find that increasing magnetic disorder flattens the electron density of states compared with the ferromagnetic case, which distorts the octahedral cages around carbon, lowering the activation barrier to diffusion; an applied field reverses these trends.

6 pages, 5 figures, 10 pages supplemental material with 3 figures

References in corpus (4)

• A Data Ecosystem to Support Machine Learning in Materials Science
• The importance of the electronic contribution to linear magnetoelectricity
• Atomic diffusion in alpha-iron across the Curie point: an effcient and transferable ab-initio-based modelling approach
• Lattice relaxations in disordered Fe-based materials in the paramagnetic state from first principles